Field of the Invention
Embodiments of the present invention generally relates to an apparatus and method for compensating a landing string below a rig floor due to movement of a floating rig platform.
Description of the Related Art
As oil and gas production is taking place in progressively deeper water, floating rig platforms are becoming a required piece of equipment. Floating rig platforms are typically connected to a wellhead on the ocean floor by a near vertical tubular called a drilling riser. The drilling riser is typically heave compensated due to the movement of the floating rig platform relative to the wellhead by using equipment on the floating rig platform. Running a completion assembly or string of tubulars through the drilling riser and suspending it in the well is facilitated by using a landing string. Subsequent operations through the landing string may require high pressure surface operations such as well testing, wireline or coil tubing work.
The landing string is also heave compensated due to the movement of the floating rig platform (caused by ocean currents and waves) relative to the wellhead on the ocean floor. Landing string compensation is typically done by a crown mounted compensator (CMC) or active heave compensating drawworks (AHD). If any high pressure operations will be done through the landing string, then the high pressure equipment also needs to be rigged up to safely contain these pressures. Since the landing string is moving relative to the rig floor, the compensation is provided through the hook/block, devices such as long bails or coil tubing lift frames are required to enable tension to be transferred to the landing string and provide a working area for the pressure containment equipment. Rigging up these devices take time and the pressure containment equipment must be rigged up at heights above the rig floor while the entire landing string assembly is moving due to the compensation. Therefore, there is a need for an apparatus and method for providing landing string compensation below the rig floor which allows for faster and safer rig up of pressure containment equipment above the rig floor.